Motion-picture apparatus and method



Dec. 8, 1953 M. E. EVANS MOTION-PICTURE APPARATUS AND METHOD l5 Sheets-Shem; 1

Filed Oct. 10, 1949 INVENT OR.

Dec. 8, 1953 M. E. EVANS MOTION-PICTURE APPARATUS AND METHOD 15 Sheets-Sheet 2 Filed Oct. 10, 1949 INVENTOR.

I'll illlL Dec. 8, 1953 M. E. EVANS 2,661,652

MOTION-PICTURE APPARATUS AND METHOD Filed Oct. 10. 1949 15 Sheets-Sheet s Has w jaw? Dec. 8, 1953 M. EvANs 2,661,652

MOTION-PICTURE APPARATUS AND METHOD Filed Oct. 10, 1949 15 Sheets-Sheet 4 IN V EN TOR.

Dec. 8, 1953 M. E. EVANS MOTION-PICTURE APPARATUS AND METHOD INVENTOR 15 Sheets-Sheet 5 Filed 001;. 10, 1949 Dec. 8, 1953 M. E. EVANS 2,661,652

MOTION-PICTURE APPARATUS AND METHOD Filed Oct. 10, 1949 15 Sheets-Sheet 6 FIG. 20 WE. 2i

INVENTOR.

Dec. 8, 1953 M. E. EVANS 2,661,652

MOT ION P I CTURE APPARATUS AND METHOD Dec. 8, 1953 M. E. EVANS 2,661,652

MOTION-PICTURE APPARATUS AND METHOD Filed Oct. 10, 1949 l5 Sheets-Sheet 9 INVENTOR.

Dec. 8, 1953 M. E. EVANS 5 MOTION-PICTURE APPARATUS AND METHOD Filed Oct. 10. 1949 15 Sheets-Sheet l0 F1652 A H555 INVENTOR.

M. E. EVANS MOT ION P I CTURE APPARATUS AND METHOD Dec. 8, 1953 Filed Oct. 10. 1949 15 Sheets-Sheet l3 INVENTOR.

Dec. 8, 1953 M. E. EVANS MOTION-PICTURE APPARATUS AND METHOD 15 Sheets-Sheet 14 Filed Oct. 10, 1949 INVENTOR,

Dec. 8, 1953 M. E. EVANS ,6 52

MOTION-PICTURE APPARATUS AND METHOD Filed Oct. 10, 1949 15 Sheets-Sheet 15 Patented Dec. 8, 1953 UNITED STATES PATENT QFFICE MOTEGN -PIC'1URE APPARATUS AND METHOD Martin E. Evans, Brooklyn, N. Y.

Appiication October 10, 1949, Serial No. 120,563

7355 Claims. 1

This invention relates to photography and more particularly to motion picture apparatus to adapt intermittent light to the photographic operation in various fields of photography.

In the usual motion picture camera there is provided an objective, a gate for positioning the film, a shutter operative between the objective and the gate, an intermittent mechanism to pull the successive increments of film past the gate, and a sprocket to propel the film, all cooperatively operated. Taking the operating range as between 24 frames per second for standard motion picture practice and 6 frames per second for the minimum practice to reproduce motion, the problem of adapting intermittent light to the photographic operation involves several factors.

First, the intermittent of light are painful to th observer where they occur at a lesser rate than 46 per second by reason of the sensation of flicker. To remove the objectionable sensation of flicker when taking pictures at 24 frames per second requires at least 2 fiashes per frame, and when operating at 6 frames per second at least 8 flashes per frame.

Secondly, with more than one fiash per frame, multiple exposures occur on the film and this is not permissible. The shutter must provide an opening to the exposure aperture only during the interval covering a flash and its accompanying dark period at most.

Again, the pull down interval should come within the dark interval of the fiash period to protect the film while it is moving from light, so it is evident that a special correlated action between the shutter, the pull down and the flashing mechanism must be established to cover the operating range previously stated.

"eason of the fixed cyclic angular relation existing between the shutter and the pull down mechanism, the durations of their operating intervals change with the change of frame rate. The chan e irom 24 frame to 6 frame rate increases the exposure and pull down intervals, so that the pull down mechanism must be established on the basis of the lesser rate interval in order to provide a dark interval short enough to accommodate 8 fiash periods with suitable dark and light intervals per flash.

It is an object of this invention to remove the limitations imposed upon motion picture photography by the limitations of the individual elements in a motion picture machine, by the assembled arrangement of those elements, and by the carrier of the photographic emulsion utilizing those elements.

All

nicng the further objects of this invention are physical assembly of motion picture machine elements for accessibility particularly of the shutter; an increase in range of shutter action; provision for phasing of the shutter; provision for colo filters to successively analyze light into its primary colors; provision for identifying the analyzed colors on exposed and developed emulsion; revision for recording on the emulsion carrier sound at the scene photographed, with monitor ing sound play back; provision for transporting the film in the camera and automatic threading of the camera; provision for overrunning operation of the pull-down mechanism; provision for conversion for high speed photography and for projection; provision for electronic light control and phasing relative to the film; and provision of a carrier for the photographic emulsion that is cheap, subject to repeated use, and adapted to be emulsion coated by the photographer.

It is a further object of this invention to provide photographic apparatus basically adapted to use in diverse fields.

Motion picture machines are operated in diverse fields and with varied lighting conditions, such as motion picture studios, news reel record-- ing, scientific investigation, stroboscopic engineering investigation, television screen photography, and color photography. The usual motion picture machine and machines designed for special fields such as television screen photography have not been readily usable in other fields heretofore. They have lacked (1) flexibility in manipulation of the shutter; (2) flexibility in moving the film in the machine; (3) flexibility in phasing the electric drive with film pull-down; (4) flexibility in primary color recording; (5) flexibility in identifying the color with its film frame; (6) flexibility in sound recording and reproduction; ('7) flexibility in film projection; (8) flexibility in the type of emulsion carrier; and (9) flexibility in exposure light control, all of which are provided by this invention. To provide any one of these is an addition to the art. To provide them collectively, making them available simultaneously in a single machine is a further addition to the art, providing new, basic and pioneer photographic apparatus. The methods of photography using this apparatus are new and basic. I Further objects of the invention and novel features will be apparent from the following specification when considered together with the accompanying drawing in which:

Fig. 1 is a front side view of a motion picture camera mounted on a tripod before a television receiver.

Fig. 2 is a plan View of a dark tunnel isolating extraneous light from that passing from the television receiver tube to the camera of Fig. 1.

Fig. 3 is a back side view of the camera of Fig. 1.

Fig. l is a front view of the camera of Fig. 1, showing the camera body shifted. to one side to give access to a shutter chamber.

Fig. 5 is a plan view of the camera of Fig. 1, with the body in shifted position.

Fig. 6 is a partial back side view showing the position of a focusing telescope and support beam for the camera body of Fig. 1, during side shift positioning.

Fig. l is a partial sectional View 01 a side shift connection between the camera body and its support on line l--'i of Fig. 6.

Fig. 8 is a sectional view longitudinally of a cantilever support for the camera body in side shifted position along line 8-8 of Fig. 5.

Fig. 9 is a sectional view along 99 of Fig. 8.

Fig. 10 is a sectional view of the camera side shifting mechanism.

Fig. 11 is a sectional view along line IIH of Fig. 10.

Fig. 12 is a partial vertical sectional view of the camera shutter and drive along the center of the shutter drive shaft.

Fig. 13 is a sectional view along line 13-43 of Fig. 12.

Fig. 14 is a gear diagram of the final gear connection to the camera shutter.

Fig. 15 is a layout of a sector for the shutter.

Fig. 16 is a vertical sectional view of Fig. 13 along line IG-IB showing a driving connection to the pull-down mechanism.

Fig. 17 is a vertical sectional view of Fig. 12 along line 11-41 showing the stop control for the rear shutter sector.

Fig. 18 is a vertical partial sectional view showing the clutch drive for the rear shutter sector.

Fig. 19 is a vertical sectional view along line l9-l9 of Fig. 18 showing the clutch drive.

Fig. 20 is a front view of a shutter ring.

7 Fig. 21 is a sectional view along line 2I2l of Fig. 20.

Fig. 22 is a partia1 horizontal sectional view through the camera shutter chamber.

Fig. 23 is a front view of the shutter chamber when open.

Fig. 24 is a divided time chart showing the relation between events on a 30 frame television tube screen and the operative activities of a motion picture machine operating at various rates.

Fig. 25 is a chart similar to Fig. 24 for a television rate of '72 frames per second.

Fig. 26 is a front view of the preferred form of shutter with the shutter chamber open.

Fig. 27 is a partial horizontal sectional view through the shutter chamber on line 21-21 of Fig. 26.

Fig. 28 is a sectional view of the Fig. 26 along line 28-28 showing overlap of radially movable sectors.

Fig. 29 is a sectional view of Fig. 26 along line ZS-29 showing the cam sector for light control.

Fig. 30 is a back view of a light control chart for recording photographically 30 frame televised 3 color values occurring in varied sequence for 6 frame camera action.

31 is a back view of a light control chart for 3 color values occurring in regular sequence for varied camera frame rates.

Fig. 32 is a back view of a light control chart for recording photographically '12 frame rate televised 3 color values at 6 frame rate camera action.

Fig. 33 is a light control chart for standard pictures at 6 frames per second taken by a flash light operating "(2 times per second.

3a is a li ht control chart for projecting pictures from a film moved 6 frames per second in the camera.

Fig. 35 is a horizontal sectional view of a phasing device between the motor and camera drive shaft.

Fig. 36 is a side view of a modified removable pull-down mechanism originally shown in U. S. Pat. 2,144,277.

Fig. 37 is a vertical sectional view of the pulldown mechanism along line 3l3'i of Fig. 36.

Fig. is a vertical sectional view of the pulldown mechanism along the line 33-38 of Fig. 37.

Fig. 39 is a horizontal sectional view of the pull-down mechanism along the line 3939 of Fig. 38.

Fig. 1G is an enlarged partial sectional view through the pull-down mechanism along the line illle of Fig. 39.

Fig. i1 is an enlarged portion of Fig. 39.

Fig. 4:2 is a view in vertical elevation of the pull-down mechanism fitted with a color screen and its operating accessories.

Fig. i3 is a vertical sectional view of Fig. 42 along line til-d3 showing the color screen installation.

Fig. 4a is a horizontal sectional view alongthe line 44-46 of Fig. 42 showing the drive connection for the color screen.

a5 is a front view of a screen driving cam.

it is another form of color screen with its mounting.

Fig. i? is an end view of the camera door swun downwardly showing the drive arm for the color screen operative from outside the camera.

Fig. 48 is a vertical sectional view through the drive shaft for film movement as shown in Fig. 1.

Fig. 49 is a vertical sectionalview along the line 49-49 of Fig. 48.

Fig. 50 is a vertical sectional view along line 50--5i3 of Fig. 48.

Fig. 51 is a diagrammatic representation of the film conveyor band and sound recorder.

Fig. 52 is an end view of the novel photographic element carried by the band.

Fig. 53 is a cross sectional view through a film and a blanking screen for color.

Referring to Fig. l, on a tripod i is mounted a pivoted head 2 with an adjusting handle 3. The head 2 carries a camera base 4 with a front upstanding member 5 on which is mounted lens 6. On the camera base t rests camera case! with grooved beams 8 and 9 between them holding the case and base in sidewise alignment by tongues from the members i and i fitting the grooves of 8 and 9. The degree of sidewise movement is shown in Fig. 4, where the outline I of the camera case 1 rests upon the beams 8 and 9 which are approximately half way extended from the base 4.

The travel of the beams Band 9 is limited by beam pins H] and H which are upstanding in grooves 12 and 13 respectively in the camera case I and depending in grooves 14 and [5 in the camera base 4. The pins are located approximately midway of the beams length. Depending shoulders or endsoi the oasegrooves l2 and I3 and upstanding shouldersor ends'of thecam'era base grooves l4 and 15 by contact with'the pin I!) Fig.

and. H respectively, limit the travel of the case over the base in the contracting direction. Stops it and ll at the ends of the respective case grooves and stops l8 and [9 at the ends of the respective base grooves limit the travel of the casein the out-going direction.

Mechanical means to shift the camera case with respect to the base on which the case rests is provided. Preferably it is located midway between the two beams 8 and 9 along section line i-l of Fig. 6, in which case to the base 4 shown in Fig. 7, a push-pull rod 20 is anchored by a fas tening 25. The rod 23 is in a channel bounded on its upper side by a wall 22 and on its lower side by a wall 23, the walls being a part of the camera case i which slide over the push and pull rod in consequence of the shift mechanism op eration. The shift mechanism may be located in the end area 23 of the case, in which situation the push-pull rod 2%? terminates in an anchor loop 5 which is held by a pin it to the base 4. The upper wall 222 extends over the rod 29 only so far as is required to retain the rod 20 and a chain extension 2'! thereof in alignment during operation of the shift mechanism shown in Figs. and 11. The chain 21 extends around a sprocket wheel 28 and between guide rails 29 and 3B which terminate in a spiral arrangement 3! providing storage for the chain 2'? during the closed position of the case 3. Although the chain storage is shown to the left of the sprocket, it may be located above the sprocket. The sprocket 28 is loosely mounted on a shaft 32 carried in bearings 33 and in the case 1. The sprocket is driven by a which it carries extending toward the rear of the case '5 and between the shoulders 35 and of a lost motion cam 38 keyed to the drive shaft 32 which is manually turned by a handle 39. Handle 39 is pinned to shaft 32. Diametrically opposed to the drive pin 35 is a groove 4-? into which fits a shoe 4i carried by a lever 42 pivoted to the case i by pin 43. From the pivot 43 the lever it extends horizontally to the shoe and then curves downwardly to connect with the lower link 44 of a toggle completed by upper link 45. The link 45 is a down projecting arm of a bell crank the other arm 46 of which extends horizontally. The free end of the bell crank arm 46 carries a handle 47 which extends through the rear wall of case i above the shaft 32. The bell crank is pivoted at E8 to an upstanding member 49 slidable between upper pins 56 and lower pins 5! anchored to the wall of case 1. The lower end of the upstanding member 49 fits into a notch 52 in the rod to hold the case I and base 4 in retracted position. The shoulder 5-3 on the lower end of the upstanding member is down pressed by a spring 54 anchored to the case i. When the members t and l are extended over beams 3 and 9 the links of chain 27 provide notches for locking in extended position.

In operation, assuming the members are in positions shown in Fig. 10, a turn clockwise of shaft 32 by crank 9 causes cam 38 to engage shoe 4i and raise lever 42 and the toggle 44-45 and the shoulder 53 against spring 54., thus releasing the case 'i to slide along tie rod 2E5. Further clockwise movement of cam 38 engages shoulder 38 against pin and forces chain links 2'! down against tie rod 20. Further clockwise movement pulls the stored chain 27 from spiral 3i and feeds it into the channel provided by members 22 and 23 of case i. Outward movement is limited by stops It and IS in the base 4. Lock at intermediate points are provided by lifting handle 47 and lever 46 which breaks the toggle 4445, the join-- ing pin 55 of which rests against the upstanding member 49. When the toggle is broken the spring forces the stop into a chain aperture.

For retraction, the handle 47 is lowered, thus the lever 48 through the bell-crank 45-44 reestablishes the toggle lock. Then the handle 39 and cam 33 are turned counterclockwise to make groove 43 engage shoe ii, raise lever t2, toggle 44-45 and so release the stop from holding position. Further counterclockwise action of cam 38 brings shoulder El against drive pin 35 and turns sprocket 28 to pull chain over the wheel from the channel between members 22 and 23. This action forces a telescopic action of the beams 3 and 9 between case i and base 4.

The outgoing action described separates case 7 from upstanding member 5 and makes accessible for adjustment the shutter disks and light control in the shutter compartment 16 of case "i to be described later.

Referring to Fig. 4, the upstanding member 5 on the base t mounts a turret disk 56 which carries four lenses b, 6!, 62, 63, lens 6 being shown in position before the film aperture. -fitetween the lenses enumerated are apertures and removable covers 6t, 65, Fifi and 671. These apertures extend through the turret disk fifi. Upstanding alongside the member 5 is a housing 68 with pivot 69 in the base 4. On pivot (is member E8 swings away from member 5 to give clearance for rotation of disk til. In the housing 63 is a light source it and a photoelectric tube l! shielded from each other. As shown in Fig. 3 and else" where, light from source it passes through aperture G5 to a revolving disk, to be later described, where the light is either absorbed or reflected back to tube H. Reflected light activates the tube "H the current from which passes to an amplifier "i2 and associated electrical devices. As shown in Fig. 1, from amplifier $2 a line through a switch 13 carries a signal to glow tube it or to a television cathode ray tube '55.

The light source it may be regarded source of radiant energy not necessarily visible since the visible part of the radiation may be screened out and only dark emanations would then be reflected back to tube l i. The tube El also be defined to include that broad classification light sensitive devices such as the selenium resistance bridge, the alkali metal photoelectric cell and the rectifier type, among the practical examples in that category.

The camera case has a front end shutter compartment accessible as previously de scribed, a front side film handling chamber if, and a rear side gear driving chamber 18 with an adjacent compartment for accessories such as electrical connections, switches, resistances, shutter adjusting lever cc and clutch control iii. From the motor {52 mounted on the rear of case extends a drive shaft 533 through the chamber 18 to the shutter A in compartment inter mediate of the motor and shutter, cross shafts take off power to drive the "n pull-down mechanism 8t and the film feed sprocket in the film handling chamber l'l.

Referring to Fig. l, on top of case i is a narrow vertical chamber 355 with removable cover and at its bottom connecting approximately niidiength with chamber ii. In the chamber 8b is an upper roll 88 and a lower pair of smaller rolls and as. To the left of the chamber at is a film suppy magazine 9! held in place by bottom bolts 32 and In the mgaazine at a film supply reel top bolt $3.

94 is rotatably mounted and is accessible by unscrewing of cover plate 95. A pair of rolls 36 and 9'! in the magazine ill guide film as it passes through light trap 98 and aperture 99 into chamber 36 to roll 8. To the right of chamber 35 is film receiving magazine Hill held in place by bottom bolts 92' and top bolt can In the magazine Hill a film receiving reel IUI is, rotatably mounted and power driven through rear pulley I02 and belt Hi3 shown in Fig. 3. Magazine Illil is closed by screw plate I'M. A pair of rolls I05 and we in the magazine IIIll guide film as it passes from roll Bil on through aperture lIli, light trap I08 to receiving reel IBI. As the film leaves roll 89 it passes downwardly and between a pair of pressure rolls 1G9, IN], on to sprocket rolls Ill and sprocket 35, on in a loop to guide roll Ill, on through the pull-down mechanism 84 and out to a loose loop, then back over pressureroll's I I3 and around sprocket 85 and upwardly to buckle roller I M and roll 95. In its passage from roll 89 around the path outlined back to roll 90 the film was in contact with an endless belt H5 which extends additionally from roll 3i. up around roll 88 and back to roll 89 to complete the endless circuit. The belt is perforated and engages the sprocket and pull-down mechanism the same as standard perforated film. 'Vhen standard film is used the belt film act a unit. By matching the perforations the belt acts as a self threading device through the film handling chamber ll. Another use for the belt is described in connection with Figs. 51 and 52.

On the lower side of pull-down mechanism a mounting M2 for a second guide roll I12, the providing inlet and exit rolls for lilzn and belt to accommodate tightoperation or t e belt through the pull-down passage for high speed continuous operation in connection with stroboscopic photography.

For continuous operation, the intermittent mechanism is rendered inoperative and serves only as a film guide. To this end the member 296 (Fig. 36 is outing to the dotted position shown, the mechanism is withdrawn laterally and suitable obvious adjustments are then made to make the drive ineffective. The pin EDI! (Fig. 3"!) is shown with a shoulder to hold it in place longitudinally when replaced after withdrawal thereof. The pins 3M (Fig. so) are shown with nut lastenings accommodating removal. With these pins removed the mechanism is turned so that the pins 2132 (Fig. 39) are withdrawn from the film. thug seen that additional facilities not needed for continuous operation of the film.

Again referring to Fig. 1, around the feed sprocket as magnetic heads I16, II'I', II8 are on arms Elli, Iii i2! respectively, which are hinged on pins I22, lZ-l respectively, and spring pressed against the film F on sprocket 85 and an associated guide the film lifts from the sprocket. The F carries material suitable for magnetic action by the heads to provide a sound record to accompany the film and be available for immediate replay. :lead HE is an erase coil fed with. high frequency energy to demagnetiae the recording material. Recording head Ill contains a main audio winding and an auxiliary high :l'reo uenc'y coil, the latter in series with the erase coil to secure proper high frequency excitation. The audio winding is preferably, energized with signal current from an audio amplifier I25. Head. IJI8 which carriesa. shield I26 to isolate it from the recordinghead, supplies, an

8 amplifier, not shown, from which the sounds being recorded are recreated and thus an immediate check on the recording is provided.

As shown in Fig. l, the camera is set up to photograph a television receiver cathode tube screen I39. The accompanying sound signals or the receiver are supplied by leads I21 and I28 to loud speaker I29 from which leads extend to amplifier I25 and to head ill for recording action on the photographic film. A dark tunnel I3Il, shown in plan in Fig. 2, and in vertical section in Fig. 1, excludes extraneous light from the lens s and tube 15. Access to the tunnel I30 is provided with side doors i3l and I32 which may be opened to provide a full View of tube I5. On door I32 is shown a light meter I33 for gauging the actinic value of the tube 75.

The original television images are usually lacking in contrast, therefore, it desirable to exelude extraneous light to take full advantage of the contrast of the image on the screen.

A suitable circuit for energizing flash tube 14 is set forth on page 230 oi Fluorescent Lamps, Forsythe and Adams, loss edition. The coil I34 around the tube It is a so called electric finger to initiate the action of the tube. The action of th electronic switch for the finger lib will be described later.

A suitable cir lit for controlling the cathode ray tube It fits into the television circuits of the tube '45 which ma be of the type having an indirectly heated cathode I35 and a control grid I35, a first anode F31 and a second anode I38. The picture appears on fluorescent screen 533. By of a suitable battery l lo connected in series with a resistor I lI the grid Ito may be kept at a suitable negative bias. Through a coupling condenser I42 picture signals are imposed upon the control grid To blank the tube the grid I36 may be driven highly negative by negative impulses generated by light 'lli and photo-electric tube Ii utilizing li ht reflected from the source "if? to the tube ll by shutter arrangement A in shutter compartment ill of case i. Other equally effective control circuits to tube may be employed, utilizing the shutter switch.

The photo-electric tube l l connected to the ingoing circuit of amplifier l? in the outgoing circuit of which no. ative impulses are carried through a conduc or l ll to the control gird I33. These inipul are represented at H4.

Operations of the tubes will be described later in connection with the shutter A in the shutter chamber.

The set-up in l is illustrative of the invention specifically applied to television. The inclusion of the tube M and control finger i34 controlled jointly with line I 33 from amplifier l2 and members ii and is, and it or substitute, along with screen I29 and lighting means '55 behind the screen, provide a, set-up analogous to that required for studio photography by intermittent light.

Referring to Fig 12, a longitudinal drive shaft 83 is shown supported by bearing its in a cross wall I5I in the gear chamber "58. hastened to the shaft 83 is a hub 152 carrying a gear Hi3 on its periphery and a tube extension ib l with an exterior gear Illli. The gear 55 meshes angularly with gear I53 fastened to a cross shaft which drives the pull-down mechanism later to be described. On an extension 83 to shaft 83 and having a. reduced diameter is a compound screw'of two members I51 and I58. These screw members are. in end to end relation to each other member I57 being keyed to shaft 83' and memhelix of member at the other end a nut Nil fitting the helix of member ibt. ll'ieinbers I59, 66 and l oi act as a long slidable nut over both helices and within the member 1 d. Beyond the helix i553 shaft sends in a reduced diameter section 83" through w ll H32 and bearing plate On the sh is scewecl the hub iii-*3 or" exter c section of fill; r shutter disk i 55. Around the hub i M a series of bearing rolls its are held by the hub 5; of interior shutter disk Around the hub iii! a series of bearing rolls ltd are held by hearing [it in the hearing plate 83. The rolls are held from longitudinal movement by member l'ii screwed on hub :67 and which carries a gear on its rirn. Gear member ll! through intermediate gear H5: is driven by a change gear ll-ll on shaft supported at one end in bearing plat i The intermediate gear H 2 is supported on a two position stud pin 112. The gears 1'53 and are have a 3 to 1 circumferential ratio and are adapted to be interchangeable in their position on shaft 4'54. The pin H2 occupies the position HE" when the intermediate gear H2 is in mesh with gear H3. The gear arrangement drives the shutters in opposite directions of rotation and at the same rate when gear lit is active but at a 3 to 1 ratio when gear H3 is active. The shu ter disk. N35 is provided with a circumferential groove on the back face thereof and opposite the groove a rib il'5 on the front face. Slots in the rib ll 5 accommodate holding plates il s which press circumferential member ill against the,

shutter desk. Circiunferentlal rib in on the front face of shutter dish itii meshes with the groove in the back of disk Slots in the rib I it accommodate holding plates 6773 which press circumferential member iiiii against disk i 53. Grooved rims i655 and ltt' are positioned around the outer edges of members ill and Hit respectively and have radial slots cooperating with radially disposed slots between members H6 and H8 respectively to hold in place sectors of a nature later described. This construction shown in Figs. and 21.

The rear end of shaft El i carried in a bear 111g in cross wall 55 i. The shaft is driven through clutch by gear it! meshing with gear Slidably mounted on shaft ilt is a rack meme her 282 operated b a meshing gear connected to shaft its supported in the longitudinal wall of gear chamber The shaft it carries exterior arm 1 13, havin a. stop pin 59! in the end thereof spring pressed. against a positioning quadrant m2 adjacent thereto. A yoke 585 at one end screwed locked to rack it? and other end encircles tubular not member Hill. The bearing is adapted to impart longitudinal motion to the nut- !Eli while accommodating nut rctatio; Such longitudinal movement is effected by veinent of gear 583 and acts to rotate members 551, 358 and the attached front shutter di I 55 relative to the drive shaft 83 and i extensions. As shown in Fig. 12 the rear end of rack is adjacent to the face it? of the clutch cone 2!! and in a position to hold with a bearing having retain-v cone member 25 I.

If) the clutch out of gear with the result that the rim gear I3! turns idly upon the clutch structure.

The shutter members ill and tilt are variously constituted, in some cases of solid metal, in other cases of transparent material and with pellicle mirror coatings and with light obstructihg sectors with suitable retaining means. The

smallest light obstructing sector provided is of 24 width shown in Fig. 15, where member I83 is shown in plan and end elevation. t is a folded 72 section of the ring having 24 sec-- tions 558 and 588 folded over the middle 24. section. Suitable positioning means for sector on the shutter are provided, as shown in Figs. 20 and 21, slots in rim i555 and matching spaces between members l'ifi through which. Y In.

the sector is fed to the retaining grooves. operation cone 2H disengage the clutch throwing shutter ill-d into open idle position. Then lever controlling shutter member ill may be operated quickly to make a single exposure when such is desired. Referring to Fig.13, the gear is supported on shaft I85 having a bearing plate i t adjacent the pulldown mechanism. and bearing iil'i. The bearing ii i supports the over-hung flywheel E98 on extension of shaft lili. Adjacent the bearing plate itii is an over-hung disk extension E99 of shaft iilaicarrying acranh pin silt-supporting a drive. block 255i. on shaft 2&3 which operates the pull-down mechanism 8 5. The connection between the block and the disk is in the nature of a radial slot covered wholly on one side by disk plate 294, partially on other side by disk plate 265 and endwise by ring 2%. The alignment of the shaft relative to shaft is offset so that the action of the drive pin and block is to provide an acceleration ofrotary movement of shaft 203 on its down drive of the pull-down mechanism 3 As shown in l6, the'sides of the slot for block 2t! are inthe nature of magnet having N and? poles between which the block' be held in radial position. when the pull- Zilil may be removed.when the camera is to be at ultra high speeds and the pull-down is;

immobilized in which case the belt lib operates continuously around guide rolls M2 and H2. The offset of shafts i535 and 253 relative to each other and to the median line of the pull-down action. is shown on line 3-6 in Fig. 16.

Referring to Figs. l7, l8 and ill, on shaft l's' l is securely mounted hub Zill with three radial arms 26%? extending to ring supporting gear till.

Gear Q83 is retained in position by flange 2% and snap ring 2 i i. In the hub AM are axial slots supporting wings 2H3 which extend radially to guide,

slots in ring 269. The wings 2H9 extend from Between the wings 2H3 and the arms 2% is a spring ring 2922 hold the shoulders 256 of wings are in engagernent with notches 25b in the gear flange 253 of gear ibi; Against cone 2i i is mounted a fork 7 25'! with stem Ell extending at right angles to shaft 1 and through a supporting bushing it in the wall of gear chamber The bushing 2ft; has an extension 2H9 internally slotted in which slides a pin through stem ill to keep the latter from rotating. On the extension fit is threaded a bushing are through which extends the stem 2. of pi 5, one on each side of the bushing 22% permitting the latter to rotate freely but trans:

The block 25: fits into a disk 23?.

which tends to Through the stem extends a pair. 

